The present invention relates to a mounting structure of a transmitter for a tire condition monitoring apparatus, and more particularly, to a mounting structure of a transmitter used in a tire condition monitoring apparatus that wirelessly transmits tire conditions such as a tire air pressure to a receiver.
Wireless tire condition monitoring apparatuses that allow a driver in a vehicle passenger compartment to check the conditions of vehicle tires have been proposed. One such monitoring system includes transmitters and a receiver. Each transmitter is located in the wheel of one of the tires and the receiver is located in the body frame of the vehicle.
FIG. 6 shows an example of such a transmitter 30. The transmitter 30 is accommodated in a rectangular casing 31. A through hole 31a is formed at each end of the casing 31 (only one of the through holes 31a is shown in FIG. 6). Projections 21a for fixing the transmitter 30 to a wheel 21 are integrally formed with the wheel 21 at positions corresponding to the through holes 31a. A recess 21b to which a bolt 60 is threaded is formed in the center of each projection 21a. Each bolt 60 is inserted into the corresponding through hole 31a, and is then threaded to the corresponding recess 21b, which fixes the casing 31 to the wheel 21.
In this structure, each projection 21a, which has the recess 21b, must be integrally formed with the wheel 21. In other words, to install the transmitter 30, the wheel 21 must be specially designed for the transmitter 30. This adds to the costs of the wheels 21. If the wheel 21 is made of thin steel plate, it is difficult to form the projections 21a integrally with the wheel 21. Further, when threading the bolts 60 with the recesses 21b, the tightening torque of the bolts 60 needs to be carefully adjusted, this need complicates the installation.